


I Trusted You, and You Let Me Down

by mylifeisloki



Category: Captain America (Movies), Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: F/M, Tumblr Prompt
Language: English
Status: Completed
Published: 2014-08-21
Updated: 2014-08-21
Packaged: 2018-02-14 03:13:27
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 5,172
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2175936
Author URL: https://archiveofourown.org/users/mylifeisloki/pseuds/mylifeisloki
Summary: <blockquote class="userstuff">
              <p>Steve and Natasha are in a completely casual, sexual relationship. Or are they?</p>
            </blockquote>





	1. Chapter 1

The cold, hard truth was that Natasha had developed an impossibly inconvenient crush on Captain America. It couldn't be described in any other way. Once they'd all moved into the Tower and she had a chance to spend even more time with him, it was clear that the strange sensation in her stomach whenever he smiled an adorably crooked smile or ducked his head bashfully was actually what other people referred to as 'butterflies'. Suffice it to say that Natasha had never experienced a real crush before. She'd been in love, true, but it was never like this.  
  
Her romance, if one wanted to call it that, with the one she knew as James was one born of mutual respect and mutual love, but it was the relationship of two brainwashed assassins desperate to feel something. If she had to pick any one word to describe the whole affair it would be a very simple decision; intense. The whole thing was inescapably intense. As for her short relationship with Clint, there was a debt owed, a debt paid, and something of a curiosity that led her to his bed. They were as close as two people could be, but her stomach hadn't ever fluttered when Clint grinned or touched her arm or sang along to his favorite songs.  
  
But Steve had this way about him that just affected Natasha in such a way that she felt like the giggling, blushing teenage girl she'd never been. Truth be told, it was terrifying. She trusted very few people and she'd never given herself so completely without even a moment of hesitation. It was just that Steve was the kind of man one could inherently trust. He was everything good, everything she wasn't, and he just happened to have this Marlon Brando smile that made her feel like she was in an old romance movie playing the lead. Natasha went from being a confident, badass assassin to being someone who actually _blushed_ when he told her she was pretty. Of course, she'd also covered for that by knocking him on his ass, pinning him to the ground, and fleeing under the guise of it having been a spontaneous training exercise. All in all, Natasha had been very on edge for the past few months.  
  
In her defense, the decision to give her heart and her trust to Steve had been made without any of her input. One day she was the same as always and the next, she was his. The only problem was that when the time came for her to tell him exactly that, she fell back on the one thing that was absolutely certain: seduction. And Steve, because deep down he was very much still a man, succumbed. She'd flirted her way right into his bed, kissing him hard on the lips once she'd pinned him in the ring and making damn sure that he knew she meant business. He'd followed without question, pressing her in turn against the wall of the elevator as they made their way back up to his floor.  
  
When it was over and Natasha was wrapped up in blue sheets and two big arms, she stared up at the ceiling and thought about how she knew what Captain America was like in bed. The short answer? Fantastic. He was just the right combination of insufferable little shit, scoundrel, and gentleman. He took what he wanted, but he gave back so much that she hardly cared at all. The truth was that she'd felt kind of cherished, listening to her name on his lips, watching him worship every single inch of her skin. It was all so genuine. And when he fell asleep beside her, it was without a hint that she should leave. It was almost as if he wanted her to stay there.  
  
But she did leave. Very, very early in the morning, she slipped nimbly from his grasp and crept out of his rooms, taking the stairs down to her own. She questioned what she had done, but it was a victimless crime, right? She got a night with him, he got a night with her... and that was all. They didn't have to worry about broken hearts or the fact that Natasha was not the kind of girl a man like Steve should be settling down with. Or so she thought.  
  
The thing about Steve was that he defied all her expectations without even thinking about it. He never said anything about the fact that she'd left without saying goodbye or waking him, but just two days later, Natasha realized what he had in mind. She was in the kitchen drinking a cup of tea at the counter and reading a novel when he approached. Of course, she was totally aware of his presence, but too curious about what he was planning to actually turn. Eventually, his arms slid around her waist and his chin rested on her shoulder, earning an arched eyebrow in return.  
  
"Comfortable?"  
"You have no idea."  
  
He kissed her neck and Natasha knew. So he wanted that kind of relationship. Alright. She could do that. She'd probably get a weekend out of him and hopefully work the good captain out of her system. Smiling indulgently, she leaned back against him and accepted a kiss on the lips as her arm lifted to slide around his neck.  
  
"In the kitchen, Captain? How very daring."  
  
There was this little smirk that stretched across his lips and Natasha decided right then and there that she really needed to make that happen more often. She was lifted up onto the counter and bracketed his hips with her thighs, drawing him in for another kiss that left them both panting, her hands eagerly unbuckling his pants and shoving her tights out of the way. Her nails bit into his skin as they fucked, leaving long, red lines over his back and shoulders, down the length of his biceps where she gripped onto him and savored how his muscles jumped and tensed and bulged with each movement, each time he pulled her into his thrusts. Thanks to a vigilant JARVIS, they were warned while panting against each other's sweat slicked skin that Stark and Barton were on their way in and hastily pulled on their clothing before hightailing it out of there.  
  
From then on, to her surprise, their relationship was exactly the same as before, but with the added thrill that was their sex life. If this was what being in a relationship was like, Natasha was a-okay with it. She was getting incredible sex, coupled with the company of a man she really liked, not that she ever told him that in those specific words, with a side helping of sly glances in the hallways or little smiles exchanged over meeting tables. It was the kind of relationship Natasha had never thought she might have wanted... but found herself really loving.  
  
The best part about it was that Steve never put pressure on her to take the next step. He never made the dopey, unrealistic comments or promises that she'd expected from a man like him. He never asked more of her than she could give. As they continued to get to know one another- physically, yes, but also through long talks late at night, with her head on his chest and his fingers lightly stroking over her spine- she came to the conclusion that it had to be real. He cared for her the way she cared for him. To be perfectly honest, Natasha was on cloud 9. She was _happy_. She really should have known that it was too perfect.  
  
All that time, over weeks that turned into months, she'd thought that the relationship they were lucky enough to have was satisfying enough for the two of them. Natasha made the somewhat foolish mistake of thinking that he saw this the way she did- as a relationship, if a slightly unorthodox relationship. But she was wrong.  
  
It happened on a Tuesday. She knew that because Steve always went jogging with Sam on Tuesday mornings and he'd just come back when he informed her that he'd be going out that night without her.  
  
"Got a hot date?", she teased, looking up from her breakfast and the newspaper spread out on the table in front of her. That's all it was- a tease.  
  
He smiled bashfully and ducked his head a little. "Well, yeah. Sort of."  
  
Oh. Natasha kept her face completely blank and looked down again, scooping another forkful of eggs into her mouth.  
  
"Who's the lucky girl?", she forced herself to ask. It was what she would have done, she told herself. Just keep breathing. Her eyes followed him as he went to the fridge, grabbing a bottle of water and chugging most of it down before answering her. She wondered if he knew what he was doing to her, if he knew how this felt.  
  
Steve turned and smiled. It broke Natasha's heart. "Sharon", he said easily. "It's nothing serious. Just thought we'd go out for that coffee, you know? Get to know each other."  
  
Natasha nodded and decided that she wasn't hungry anymore. "Well, have fun, soldier", she said, leaning on her skills of deception to get her through putting her plate in the sink and patting his chest like she wasn't breaking inside. "Don't do anything I wouldn't do."  
  
Back in her room, Natasha closed the door and locked it, taking a seat on the edge of her bed. She should have known. How stupid could she be, thinking that Steve Rogers himself would bring himself down to her level? How fucking _stupid_ could she be, thinking that this was real? She had guessed that not saying anything about only wanting sex would have insinuated otherwise, but what she hadn't anticipated was that he'd assume not saying anything at all meant that she only wanted what they had to the naked eye- friendship, and sex. Well, it didn't matter. She wasn't going to let anyone know that she'd fallen for him. She wasn't going to let anyone see that she was hurt. But Natasha didn't leave her room again that night and, without much difficulty, managed to avoid Steve the whole day.  
  
And the next day.  
  
And the day after that.  
  
Five days later, she was padding silently towards the stairs to get to the gym and stopped in her tracks, hearing Stark's voice loud and clear from the kitchen. "Still can't believe you stayed out all night", he praised. "Good for you, Cap. It's about time you let your hair down." Natasha pressed her lips together and everything went kind of fuzzy for a moment, until she heard her name.  
  
"Hey, have you see Tasha around recently? I feel like I haven't seen her in days."  
  
Another voice piped up and Natasha nearly cringed. "If you haven't seen her, that's because she doesn't want to see you", Clint explained, grumbling to himself- and it sounded like his mouth was full. There was a pause after that and she had to hold her breath to make sure that she wasn't missing anything said in very low tones.  
  
"Oh", Steve answered eventually, clearly puzzled. "Why d'you suppose that might be?"  
  
'Don't do it', she thought to herself. 'Don't. Don't fucking do it.' Clint knew, of course, what she and Steve had been up to. Natasha figured everyone on the team had an inkling, at least, and that was why Stark had gone quiet- he didn't know what to say. As usual, the theoretical telepathy that she and Clint had going on never worked when it was really, really important.  
  
"Why the fuck do you think?", he barked, and Natasha actually cringed, listening to his chair scrape across the floor before he paused, theoretically pointing at Steve himself and-- "Stay away from her", he warned, turning on his heel and marching away before anything else could be said.  
  
Natasha ran. She made it all the way down to the gym and was working out for an intense forty five minutes before someone cleared their throat and she turned. Fuck. Unfortunately, nothing actually came out of her mouth. She stared at him, panting heavily, and tried to resist either slapping him silly or running in the other direction, scaling the wall and darting out of the nearest window.  
  
"Hey, Nat", he greeted, rubbing at the back of his neck. "Haven't seen you in a few days."  
  
Fuck him. How dare he? How dare he?  
  
Steve soldiered on. "Are you avoiding me? Because it kind of feels like you are and I'd kind of like to know why..."  
  
Natasha's jaw tensed.  
  
"..I mean, we were fine just a few days ago and I can't imagine.."  
  
She was going to kill him.  
  
"...what I might have done to make you mad at me..."  
  
Maybe not kill him, but something very close.  
  
"So, what's wrong?"  
  
In a smooth movement, Natasha sprang up, wrapped her thighs around his neck and flipped him over, where he landed on his back with a satisfying thud. As she landed on her feet again, she pushed her hair back and huffed.  
  
"Nothing."  
  
And she was off. Poor Steve didn't know what hit him.  
  
It went on like that for a while. Steve would say something to her and Natasha's sarcasm came up like a sharp, barbed defense mechanism, tearing him to shreds each and every time. She was hurt. And when Natasha was hurt, it meant other people got hurt so the attention was off of her, because if people actually looked, they'd realized she was humiliated. He'd made a fool of her in the worst way possible, in a way no one had ever dared to do before. The worst part was that she _knew_ he saw Sharon again. She knew every time he dressed up and went off to meet her. She knew when Steve didn't come home and she especially knew when he brought her to dinner at the Tower- a dinner she didn't attend. It was almost two weeks until he cracked, one day after she'd reacted to his hand on her shoulder by leaping backwards, wrenching it behind him and pinning him on his stomach, one unforgiving hand on his upper back.  
  
"Alright, what is your problem?", he exploded, marching into the living room and standing in front of her, hands on his hips. "What the fuck did I ever do to you?"  
  
Natasha didn't even look up from her book. "Go away, Rogers. I'm not in the mood."  
  
No one had ever accused Steve of being a wise man. "No, I'm not going anywhere", he refused, reaching out to take her book and getting an ice cold hand around his wrist, thumb pressed to the weakest point like she could break it with just one more movement. "Let me go."  
  
"Let go of my book."  
  
They glared at each other for a few seconds before Steve let go and, one millisecond later, Natasha did the same. Steve didn't go anywhere, though, and Natasha was all too aware of his presence there, pacing up and down the length of the living room.  
  
"I'm not just something you can throw away", he argued, almost talking to himself. "We were good friends. Better than good friends! What the hell happened?"    
  
She didn't answer.  
  
"Natasha, I'm talking to you."  
  
Nothing.  
  
Steve might have snapped a little. She wasn't sure, but a second later, she was being hauled off the couch with two inhumanly strong hands at her upper arms, digging bruises into her skin. Her feet dangled two inches off the floor and Natasha thought about kicking him in the balls so Sharon might not get any tonight.  
  
"What is it? Is it me? Did I do something? Or is Barton right? Are you jealous?"  
  
He looked so infuriatingly understanding and she struggled in his grip, but he had an iron seal around her arms, limiting her movement.  
  
"Is that what this is about? You're too proud to admit that the thing with Sharon makes you jealous?"  
  
Natasha scowled. "I'm not jealous."  
Steve raised his eyebrows. "Sure seems like you are."  
  
That was enough. Using his stomach as leverage, she flipped and wrenched herself from his grip, landing behind the couch she'd been sitting on and giving him a look. Fine. He wanted an answer? He'd get one.  
  
"I trusted you", she said, her voice cold and even as the day was long. "And you let me down."  
  
She left him there, staring after her with his lips parted and looking for all the world like he finally understood that what he'd been thinking he knew was wrong from the very beginning.


	2. Chapter 2

**Summary for the Chapter:**

> Steve's POV.

When it all started, Steve had known that he couldn't keep Natasha forever. He'd been sweet on her for ages, always trying his best to spend time with her and taking extra pains to draw her properly in his sketchbooks, but she wasn't the type to be tied down, least of all to someone like him, and so he enjoyed what they had until he convinced himself to move on. He hadn't expected her to react the way she did, but he supposed he'd never been really good at reading women. Peggy had been totally right about that after all- he didn't know a bloody thing about the fairer sex.  
  
Sharon was nice, that was all. She was nice, and she had a connection to him that no on else did, and she was easy to talk to. That first date went pretty smoothly, so he let her kiss him and promised to call her again. Not one to break a promise, especially one so easy to fulfill, he'd called her a few days later and asked her out again.  
  
That time, he didn't come home until morning.  
  
What Natasha didn't know about him was that he'd only had sex prior to her with one other woman. He was hardly the blushing virgin that people made him out to be, but with the war and everything, he just hadn't had the time. One night while he was on tour as Captain America, a chorus girl had gotten friendly with him and it just _happened_. It was amazing, as first times go.. or he hoped it had been, and he moved on. But when Natasha pinned him like she had and kissed him, all passion and fire and an impossibly irresistible roll of her hips, he realized what he'd been missing. Sex with Natasha was an _experience_. She brought out this playful, bold guy in him that Steve kind of loved being. She made him better. Even when they were just laying in bed and talking, Steve was perfectly content.  
  
It didn't hurt that the sex itself was mind-blowing. The first night was just the beginning, really. They had sex in the kitchen, in the shower, in their beds, against walls, in the gym... Steve hadn't realized until just then how many _surfaces_ there were in the Tower, available for their use at all times. He never even began to get tired of it, not with how she responded to him and how eager she was, certainly not with how she took what she wanted, unapologetic and bold as ever. Truth be told, it was while she was riding him one night, breasts bouncing, fiery curls falling down her back, thick words in Russian falling from her lips, that he found himself thinking that he could do this for the rest of his life.  
  
It really wasn't until a couple of months later when he caught himself nearly telling her that he loved her that he snapped out of his little delusion and decided to make that change, for both their sakes. He couldn't keep using her the way he was and if he stayed any longer, he knew it was going to wind up hurting him the most. Natasha had never indicated that she wanted more than what they had, which Steve figured was a 'friends with benefits' kind of thing. She wanted the sex. Well, that was fine and all, but Steve wished he could take her dancing. He wished, even if he was happy with their relationship, that he could tell her she looked beautiful, that he was so glad she'd picked him, that he loved her. But... he couldn't risk their friendship for that, not when he was so incredibly unsure of how she felt towards him.  
  
So, he did what she'd been telling him to do from the beginning and asked Sharon out for coffee. And in the end, that left him standing in the living room feeling like he had a stone in his belly that had just ripped through the bottom to rest at his feet. She'd trusted him? With what? What the hell did that mean and why was she always so goddamn cryptic? It took someone who'd spent a lot of time with her to know, but the proud way she held up her chin and a glint in her eye told him the truth- she was really hurt. But hurt by what? Hurt because he was going out with Sharon now? Wasn't that what she wanted? Was _that_ why Barton had told him off? Because he wanted to protect Natasha?  
  
Heaving out a frustrated sigh, Steve let her go and sat down, covering his face with his hands. What was he supposed to do now? He couldn't just go after her and proclaim some kind of love. He couldn't.. make a fucking fool of himself and tell her that he'd actually looked at engagement rings in a store window either. She'd laugh at him. She'd say marriage was for idiots and love was for children and the weakening friendship they had would be gone for good. But.. wasn't it on its way out already? Natasha barely spoke to him anymore and when she did, it was all insults, thinly veiled remarks about his character and how he acted. Was she just too proud to admit the truth? Or was she really done with him?  
  
There was no way Steve would be able to go on with his life if he didn't know for sure.  
  
He let her calm down for a day before he did anything at all, simply because Steve was going to try to have this conversation without winding up on the floor in pain-- and because he had to speak to Sharon. Their conversation was brief and Steve told her the truth. He was in love with someone else and he had to see that through before he could move on. She understood, though he could see she was a little hurt, and he apologized before they hugged and went their separate ways. The next day, however, was all about Natasha. He decided to see her in the evening, right after dinner. She answered the door after fifteen minutes of him standing there once he'd knocked, stubbornly humming a song and waiting.  
  
"Can I help you?"  
  
Steve turned suddenly and was met with two hard, cold eyes that stared right up at him like he had no right to be there, no right to question her.  
  
"I think we need to talk."  
  
Natasha shook her head a little and stepped back, moving to close the door-- but he stopped it suddenly and met her slightly terrifying gaze.  
  
"Please."  
  
Her eyes narrowed and Steve was sure he was going to wind up twisted up into some cartoonish knot on the floor, but she just shrugged and disappeared into her room, silently allowing him entrance. He followed her, closing the door behind him and gesturing for her to sit on the bed.. not that she listened. She stood with her arms crossed over her chest, one hip jutting out, a no-nonsense look on her face that had probably challenged the descent of several pairs of balls.  
  
"Anytime, Captain", she taunted. "I haven't got all day."  
  
By the time Steve even realized how he'd reacted, it was far too late. Sometimes super-human reflexes meant acting without thinking things through and Steve felt like he was going to pay dearly for what he'd just done, in the midst of Natasha glaring daggers at him. He was dead meat. Goodbye, cruel world because she was going to kill him in the slowest way she knew how. He caught himself just pulling back, her head cradled between his hands, the growl he'd let out still emanating in his chest, his lips just an inch from where they'd been a moment ago. Uh oh.  
  
With her back against the wall, Natasha could _almost_ pass for helpless. Steve knew better, of course, and he jumped back like an idiot, stammering apologies.  
  
"If, uh.. If you don't mind, I'd prefer to die in a fight, not because of a kiss", he quipped. He'd always known his mouth would be the death of him. Looking up, he stared back at her and tried to read her expression, but it was all for naught. She was a closed book at times like these, though he could have sworn her lips quirked in a shadow of a smile, probably amused by what he'd done and what he said .. It was probably the scariest almost-smile he'd ever seen. The worst part was that she didn't _say_ anything, which meant that he just had to make up for that.  
  
"Look, I just think we need to talk about misunderstandings because I feel like you probably thought something that I wasn't thinking or.. or maybe I didn't see a clue I was supposed to see, but you're not exactly the easiest person to read, so if you wouldn't mind giving me a hint or something, I'd appreciate it. And by hint, I mean like a big fucking neon sign because I'm kind of lost and I really want to say the right thing for once, so if you could just kind of end the mystery and tell me what I'm missing here... I mean, I'm getting mixed signals. I think that's the way to put it. One minute we're fine and the next, you're pinning me and really, that just turns me on more than anything else, but it's the words that got to me... Maybe we should just be real plain about it and say what we really think and then we'll understand each other. Not that I want to come out and tell you half the shit I should, but you should probably know that I've actually, actively envisioned the kind of engagement ring I'd like to give you one day and if you want to put your thighs around my head for that, well, I kind of encourage it because I'd like to have them around me again one more time, one way or another--"  
  
He didn't realize until several moments of hopeless monologue-ing later that she was laughing. Not just tongue-in-cheek laughter, but full blown belly laughs, her hand pressed to her side as she bent forward and tried to keep her breathing steady. Steve had heard her laugh before, of course, but never like this. He'd never seen her whole face light up with it, tears springing to her eyes, her cheeks flushed a dark shade of pink. He went quiet, hands at his sides, and just watched her. Admittedly, heat crept up his neck to his cheeks and the tips of his ears, but he was way too distracted watching Natasha to care. She looked so _young_ in that moment, so happy. Steve was enchanted- that was the only word he could use to describe how he was staring.  
  
"Um", he said eventually, articulate as ever, head tilted cautiously to the side. "I'm not sure if this is a dream or a nightmare. Should I be happy or embarrassed?"  
  
Natasha stood up straight and rolled her eyes, stepping closer to him so she could easily slide her arms over his shoulders and peer up at _her_ captain, his hands settling naturally on her waist.  
  
"Maybe a little bit of both", she teased, giving him an amused look. Steve gave her that crooked smile she loved-- yes, loved-- and Natasha smiled right back. "Captain, you're going to make me weak in the knees."  
  
He laughed, low and easy, and Natasha tilted her head up as he tilted his down, kissing the spot just below his ear. "I can't imagine you getting weak in the knees for anyone." If only he knew. Natasha shifted to lift his head and pressed their lips together, savoring the way he leaned into her and leaning right back into him like she belonged there.  
  
"Not that I wouldn't want you being weak in the knees for me", he continued, undeterred. "But I can actually see me being weak in the knees for you way more often, you know? I mean, you're stop-me-in-my-tracks gorgeous and I swear, one of these days I'm going to walk into a wall because I was too busy watching you move--"  
  
" _Steve_."  
  
He stopped short and blinked down at her, raising his eyebrows.  
  
"Shut up."  
  
She kissed him hard this time, jumping up to wrap her legs around his waist and her arms around his neck. Steve's hands went under her bottom to hold her up, eventually stepping backwards towards the bed and falling with all the trust in the world, settling her on top of him. As they tugged each other's clothing off, tossing it aside as eagerly as they had the very first time, Steve flipped them over and kissed her neck, working his way down between her breasts.  
  
"I think I owe you an apology", he murmured against her ribs.  
  
Natasha huffed out a laugh, but that quickly turned into a moan as he pushed her legs apart and continued, pressing hot kisses over her stomach, over the soft skin on her inner thighs and finally pressing his mouth down between her legs. Her hands went right to the back of his head and she arched her back to get more, panting and moaning for him exactly the way she knew he wanted her to. Bless that man's mouth- he /really/ knew how to say he was sorry.  
  
In the morning, when Natasha led Steve into the kitchen with their fingers laced together, wearing only his tshirt and a pair of panties, she took particular pride in how fast Stark's jaw nearly hit the floor at the sight of them. Steve had that goofy smile on his face and it only added to her good mood, but she couldn't resist taking advantage of the fact that everyone with the exception of Thor, who was focused on his breakfast, was looking at them. She leaned up to her soldier, kissing him nice and slow, her hands on his chest.. because as he knew by then, public displays of affection made people very uncomfortable.

**Author's Note:**

> Thanks for reading! <3


End file.
